Drive power transmission device
AssigneeNissan Motor Co., Ltd.
InventorTomohiko Tanaka
Life of this patent
Estimating the term…
Abstract
During switching of an input rotation transmission mechanism, the actual engine rotational speed at the start of the switching and the speed changing ratio change amount owing to the switching operation are used as a basis for computing the target engine rotational speed of an engine and for computing the target speed changing ratio for an automatic transmission such that the rotational speed of automatic transmission on the side toward input rotation transmission mechanism nearly matches the rotational speed of input rotation transmission mechanism on the side toward automatic transmission, and shifting operation control for automatic transmission is executed in the opposite direction that is synchronized with the switching operation of input rotation transmission mechanism.
Claims20
A drive power transmission device coupled to an engine, comprising:
- an input rotation transmission mechanism having a low-speed stage that reduces an engine rotational speed from a direction of the engine and a high-speed stage on a up-shift side with respect to the low-speed stage, the input rotation transmission mechanism operable to select either the low-speed stage or the high-speed stage through a switching operation;
- an automatic transmission in series with the input rotation transmission mechanism, the automatic transmission operable to perform gear-shifting operations for rotation coming from the direction of the engine;
- target engine rotational speed computing means for computing a target engine rotational speed of the engine for an operation of shifting the automatic transmission in a direction opposite to a switching direction of the switching operation based on the amount of change in the speed-changing ratio realized by the switching operation and an engine rotational speed at a start of the switching operation when the input rotation transmission mechanism executes the switching operation between the low-speed stage and the high-speed stage;
- and
- target speed-changing ratio computing means for computing a target speed-changing ratio for the automatic transmission so that its rotational speed on a side toward the input rotation transmission mechanism is nearly equal to a rotational speed of the input rotation transmission mechanism on the side toward the automatic transmission at an end of the switching operation;
- and wherein the automatic transmission is operable to shift to the target speed-changing ratio in synchronization with the switching operation of the input rotation transmission mechanism.
A drive power transmission device including an engine that generates drive power to wheels, comprising:
- a main transmission operable to change a rotational speed of an output shaft of the engine and to transmit the drive power to the wheels;
- a secondary transmission between the engine and the main transmission operable to change the rotational speed of the output shaft and to transmit the drive power to the main transmission;
- and
- transmission control means for controlling respecting transmission gear ratios of the main transmission and the secondary transmission, the transmission control means operable to control the main transmission to change its transmission gear ratio at least one of toward deceleration while the transmission gear ratio of the secondary transmission changes toward acceleration and toward acceleration while the transmission gear ratio of the secondary transmission changes toward deceleration, and operable to complete changing the transmission gear ratio of the secondary transmission after the main transmission reaches a target transmission gear ratio.
A control method for a drive power transmission device, comprising:
- determining whether a transmission gear ratio of a secondary transmission furnished between an engine and a main transmission is to be changed;
- calculating a target transmission gear ratio of the main transmission;
- initiating a change of the transmission gear ratio of the secondary transmission;
- initiating a change of the transmission gear ratio of the main transmission after initiating the change of the transmission gear ratio of the secondary transmission;
- completing the change of the transmission gear ratio of the main transmission;
- and
- completing the change of the transmission gear ratio of the secondary transmission after completing the change of the transmission gear ratio of the main transmission.
Dependencies are inferred from the claim text.